Hydrangea macrophylla plant named ‘PIIHM-II’

ABSTRACT

A new and distinct cultivar of  Hydrangea macrophylla  plant named ‘PIIHM-II’, characterized by its remontant (reblooming) trait, flowering on old wood and new growth of the season; dark pink mophead inflorescences in non-aluminum based media and violet-purple inflorescences in aluminum based media; inflorescences that age to rose-red and remain showy for an extended period of time; compact, rounded to spreading growth habit; dark green foliage; red stems; and resistance to powdery mildew.

Genus and species of plant claimed: Hydrangea macrophylla (Thunb.) Ser.

Variety denomination: ‘PIIHM-II’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofHydrangea macrophylla, a member of the Hydrangeaceae family, hereinafterreferred to by its cultivar name ‘PIIHM-II’. This cultivar is grownprimarily as an ornamental for landscape use and for use as a pottedplant. The cultivar originated from an open pollination of Hydrangeamacrophylla ‘PIIHM-I’ (U.S. Plant Pat. No. 20,176) in Watkinsville, Ga.in 2009, and was selected from the progeny by continued evaluation forgrowth habit, floral, and foliage characteristics.

‘PIIHM-II’ has been asexually reproduced by softwood cuttings since 2009in Watkinsville, Ga. The characteristics of the cultivar have beenstable and reproduced true to type in successive vegetative generations.

SUMMARY OF THE INVENTION

‘PIIHM-II’ has not been observed under all possible environmentalconditions. The phenotype may vary somewhat with changes in light,temperature, soil and rainfall without, however, any variance ingenotype.

The following traits have been observed and represent thecharacteristics of the new cultivar. In combination thesecharacteristics distinguish ‘PIIHM-II’ from all other varieties incommerce known to the inventor.

-   -   1) Remontant (reblooming) trait, flowering on old wood and new        growth of the season.    -   2) Dark pink mophead inflorescences in non-aluminum based media        and violet-purple inflorescences in aluminum based media.    -   3) Inflorescences that age to rose-red and remain showy for an        extended period of time.    -   4) Compact, rounded to spreading growth habit.    -   5) Dark green foliage.    -   6) Red stems.    -   7) Resistance to powdery mildew.

‘PIIHM-II’ is distinguished from its female parent ‘PIIHM-I’ by itsinflorescence type, flower color, foliage color, stem color, and itsgrowth habit. ‘PIIHM-II’ has dark pink mophead inflorescences innon-aluminum based media and violet-purple inflorescences in aluminumbased media, whereas ‘PIIHM-I’ has bright pink lacecap inflorescences innon-aluminum based media and pink-purple inflorescences in aluminumbased media. ‘PIIHM-II’ has thicker, darker green leaves than ‘PIIHM-I’.‘PIIHM-II’ has red stems, whereas ‘PIIHM-I’ has pink-red stems.‘PIIHM-II’ has a more compact growth habit than ‘PIIHM-I’. There are noother cultivars of Hydrangea macrophylla with this combination of traitsknown to the inventor.

‘PIIHM-II’ can be compared to the cultivar ‘After Midnight’ (notpatented) but differs in the following characteristics. ‘PIIHM-II’reblooms throughout the growing season, whereas ‘After Midnight’ doesnot. ‘PIIHM-II’ has richer and darker flower color than ‘AfterMidnight’. ‘PIIHM-II’ has improved resistance to powdery mildew comparedto ‘After Midnight’.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying illustrations show characteristics of the new cultivarin photographs as true to color as is reasonably possible to make inillustrations of this nature. Colors in the photographs may differslightly from the color values cited in the detailed botanicaldescription which accurately describe the colors of the new Hydrangea.

FIG. 1 shows a two-year-old ‘PIIHM-II’ plant grown without aluminum withmature and aged inflorescences.

FIG. 2 shows an inflorescence on a two-year-old ‘PIIHM-II’ plant growingwith aluminum.

FIG. 3 shows a close up of a stem and mature foliage of a two-year-old‘PIIHM-II’ plant in summer.

DETAILED DESCRIPTION

In the following description, color references are made to The RoyalHorticultural Society Colour Chart, 2007 Edition, except where generalterms of ordinary dictionary significance are used. Plants used for thedescription were grown in 11.8 L containers under 50% shade underoutdoor conditions in a nursery in Watkinsville, Ga. Plants were about 2years old when the description was recorded. Two groups of plants wereused for the description to describe the flower colors with and withoutaluminum. The first group was grown in a medium consisting of compostedpine bark, with no aluminum present and a pH of 5.7. The second groupwas grown in a medium consisting of composted pine bark that was amendedwith 45 grams of aluminum sulphate and a pH of 5.7. Aluminum onlyaffects flower color. Therefore, colors with and without aluminum areonly specified for floral parts.

-   Botanical classification: ‘PIIHM-II’ is a cultivar of Hydrangea    macrophylla.-   Parentage: The current variety is a progeny from an open pollination    of Hydrangea macrophylla ‘PIIHM-I’ (U.S. Plant Pat. No. 20,176).-   Propagation: Vegetatively by stem cuttings.-   Plant description: The claimed variety is a compact, rounded and    spreading deciduous shrub. The original plant, now about 4-years-old    in the ground, is about 91 cm in height from the soil level to the    top of the inflorescences, and about 109 cm in diameter. Freely    branching. The plant is cold hardy in USDA Zones 5 to 9.    -   -   Stems.—First year stems have a diameter of about 4 mm, a            round shape, and a stout and lustrous texture with very fine            pubescence.        -   Exfoliation.—On second year and older stems, flaky and            stringy, color 161A. Internodes have a length of about            4.1 cm. The stem color is 178A. Second year stems have a            diameter of about 6 mm or more and are N199D in color.        -   Vegetative buds.—Arrangement: opposite. Shape: Ovoid. Size:            About 2 mm in length, about 1 mm in width. Color: 178A.-   Leaves:    -   -   Size.—About 10 cm in length and about 5.9 cm in width.        -   Shape.—Ovate, with acuminate apex, cuneate base and serrate            margin.        -   Texture.—Upper surface is thick and leathery covered with a            fine pubescence, 155A in color; lower surface is thick and            leathery with tuffs of pubescence, 155A in color, in the            axils of the secondary veins.        -   Color.—Emerging leaves are 139A on the upper surface and            147B on the lower surface; mature leaves on the upper            surface are 147A, and 147B on the lower surface.        -   Winter leaf color.—On the upper and lower surface 53C.        -   Venation.—Pinnate, veins are 182A at the base of the leaf            changing to 146D in color on the majority of the upper and            lower surfaces.        -   Petiole.—About 1.3 cm in length and about 2.5 mm in            diameter, upper and lower surface smooth and glabrous, and            183B in color. Petiole is grooved on upper side and            crescent-shaped in cross section.-   Flowers:    -   -   Inflorescence bloom period.—Early summer to first frost in            fall. An inflorescence contains about 68 individual fertile            flowers. An inflorescence contains about 443 individual            sterile florets.        -   Inflorescence shape and size.—Mophead, about 7.5 cm in            height and about 13 cm in diameter. The inflorescence is            effective for about 8 weeks. The peduncle is about 5.1 cm in            length, is finely pubescent, and is N77D in color with            aluminum and 61B in color without aluminum. The pedicels are            about 1.2 cm in length, finely pubescent, and N77D in color            with aluminum and 61B in color without aluminum.        -   Flower bud size.—About 2 mm in length, about 2 mm in            diameter.        -   Flower bud shape.—Round.        -   Color.—86B when grown with aluminum, and N74C when grown            without aluminum.        -   Sterile florets.—Are about 2.1 cm in diameter. Each floret            contains 4 sepals about 1 cm in length and about 9 mm in            width. Sterile floret shape: Ovoid with obtuse apex, acute            base, and entire margin. Texture: Smooth with no pubescence.            Color at maturity: With aluminum, the upper surface is N82A            and the lower surface is N82C. Without aluminum, the upper            surface is 71B and lower surface is N74D. Color of aged            sepals: With aluminum, the upper and lower surfaces are            185B. Without aluminum, the upper and lower surfaces are            184C.        -   Petals (fertile flowers).—Size: 5 petals per flower, about 3            mm in length and about 1.5 mm in width. Shape: Ovate, with            acuminate apex, truncate base, and entire margin. Texture:            Smooth with no pubescence. Color: At peak of bloom the upper            surface of the petals is N88A and the lower surface is N88B            with aluminum. When grown without aluminum the upper surface            of the petals is N74C and the lower surface is N74D.        -   Sepals.—5 per flower, 1.5 mm in length and 0.75 mm in width.            Color of sepal: On upper and lower surface with aluminum            N88B. Color of sepal: On upper and lower surface 62B without            aluminum.        -   Number of stamens.—6 to 10.        -   Anthers.—About 1 mm in length and about 0.5 mm in width.            N88A in color with aluminum and N80B in color without            aluminum.        -   Filaments.—About 3 mm in length and N88B in color with            aluminum and N80A in color without aluminum.        -   Pollen.—155D in color, produced in moderate quantities.        -   Pistil.—Superior, about 3 mm in length and about 1.5 mm in            width, N88A in color with aluminum and N74B in color without            aluminum.        -   Stigma.—Usually 2 but sometimes 3 per pistil, round in shape            and N88B in color with aluminum and 76A in color without            aluminum.        -   Style.—About 2 mm in length and tubular in shape, N88A in            color with aluminum and 71D in color without aluminum.-   Fruit: The capsule fruit is ovoid, about 3 mm in length and about 2    mm in width. The color during early ripening is close to 54B and at    maturity is close to 200C. The number of fruit per infructescence    varies widely.    -   -   Seed.—The seeds are round, about 0.5 mm in length and about            0.5 mm in width, close to 199B, and each capsule contains            about 50 seeds.-   Plant hardiness:    -   -   Plant hardiness.—USDA Plant Hardiness Zone Map (2012): Zone            5 to 9.-   Disease/pest resistance: Resistant to powdery mildew. No other pest    or disease resistance/susceptibility has been observed.

I claim:
 1. A new and distinct Hydrangea macrophylla plant named‘PIIHM-II’, substantially as illustrated and described herein.